I have the same patch for say "A" across all my banks, because i try to keep my banks all the same with only one different tone in 'D'. So when i change my main rhythm patch 'A', i have to copy it to 'A' in all 16 banks. I may have one bank that i decided to add some flange for my rhythm patch. As i copy to all 16 banks at warp 12, it invariably gets copied over....crap!

No changes are permanent until you use the "Send" button on the top left corner. To restore your HD to the previous state, just power cycle it. Once you use the send button, you're SoL. You can selectively use the Send function to overwrite one or more selected patches, an entire set list, or the entire device.